Communication systems are known to comprise a plurality of communication units, a limited number of communication resources that are transceived via repeaters or base stations, and a communication resource allocator that allocates the limited number of communication resources among the communication resources. The communication units are typically arranged into communication groups such that when a communication unit is allocated a communication resource, that resource is allocated to the communication group of that particular communication unit. In some circumstances, the communication unit may be requesting communication resource for a private call, i.e, a one to one or telephone call where only the requesting communication unit and the target communication unit have access to the allocated communication resource. Note that a communication resource may be a time division multiplex (TDM) slot(s), a carrier frequency, a pair of carrier frequencies, or any other RF transmission means.
When the communication unit is involved in a communication with its communication group, the communication is typically carded out in half duplex fashion, i.e. the communication unit cannot simultaneously transmit and receive voice dam. While the communication unit is operating in a half duplex mode, its operator typically has the communication unit mounted in a vehicle, or on his or her person. Whether the communication unit is mounted in a vehicle or on the operator's person, it is a substantial distance from the operator's ear such that the volume levels need to be set at reasonably high levels for the operator to adequately hear received audio signals.
When the communication unit is involved in a one to one communication, the communication unit is operating in a full duplex manner, i.e. the communication unit can simultaneously receive and transmit audio data. Typically, when an operator is using his or her communication unit is this fashion, the communication unit is relatively close to the operator's ear such that the volume levels need to be at a relatively low level in comparison to volume levels when the unit is operating is a half duplex mode.
As is known, recent advancements in technology have combined full duplex and half duplex operations in to one communication unit. When the operator switches from full duplex mode, i.e. a one to one telephone call, to a half duplex mode, i.e. a group dispatch call, or vis versa, the operator must adjust the volume level. In one instance, the operator may not hear the communication and in the other, the operator may have his or her ear drum damaged. Neither case is advantageous for an operator. Therefore, a need exists for a method and means that provides automatic switching of audio levels when a communication unit is switched from full duplex operation to half duplex operation.